1. Field of the Invention
This invention relates to solar heated building structures such as dwellings and the like, and more particularly, to such building structures wherein a concrete slab forms a portion of the building structure foundation and functions as a heat sink.
2. Description of the Prior Art
Building structures such as dwellings have been constructed on concrete slabs forming a major element of the building foundation. It has been determined that the concrete slab may act as a thermal storage device or heat or cold sink due to its affinity to store heat or cold for relatively long periods of time. Such concrete slabs have been formed to carry internal piping or conduits for the circulation of a liquid which is employed in the pick up of thermal energy by radiation upon a collector or heat exchanger mounted to the roof and facing the sun, whereby, during daylight hours thermal energy may be picked up by the collector and transferred to the slab, while during the night, the circulation of liquid within the piping embedded within the concrete may be employed in lowering the temperature of the rooms within the solar heated dwelling by transmitting thermal energy to the collector on the roof for dissipation to the now cooler external air. Such a solar heated dwelling is the subject matter of U.S. Pat. No. 4,000,851 issuing Jan. 4, 1977, to Volkmar Heilemann. In addition to storing heat within the concrete slab, a layer of rocks may be interposed beneath the concrete slab and in direct contact with the slab such that the rocks themselves act as a thermal storage mass and form part of the thermal heat sink.
Such solar heated dwellings are costly due to the expense of piping and circulation of the liquid between the heat exchangers constituting solar collectors on the roof and the concrete slab and mass of rocks acting as a heat sink for the concrete slab building structure. Further, such concrete slabs tend to transmit heat directly to the ground above the frost line resulting in a great loss of heat during winter operation and a reduction in efficiency of the system. Further, the bottom of the heat sink assembly, as constituted by the upper concrete slab and the lower mass of rocks, is normally completely thermally insulated from the ground, and while this prevents loss of heat from the heat sink to the ground, it fails to make use of a natural source of low temperature thermal energy.